MONTPELIER — More than a year after U.S. immigration authorities sought to split up a same-sex, bi-national couple living in Vermont, Sens. Patrick Leahy of Vermont and Susan Collins of Maine are pushing legislation to protect such couples.

After a threatening letter from U.S. Citizenship and Immigration Services 14 months ago, Frances Herbert and Takako Ueda of Dummerston got a follow-up letter in May saying the agency would hold off for two years before trying to deport Ueda to her native Japan for an expired visa.

Now legislation introduced by Leahy and Collins — backed by President Barack Obama — would halt such deportations by allowing Americans to sponsor their same-sex “permanent partners” who are immigrants for permanent residency.

There are an estimated 36,000 same-sex, bi-national couples in the country.